Your points need to be available for the date your reservation begins. So for a reservation in December 2012 you can easily use your 2012 points even though you make your reservation at the 11 month mark.
BTW, also for a reservation in your 2012 UY (August 1, 2012 through July 31, 2013), you can borrow points from your 2013 UY if needed.
Welcome Home and enjoy your first reservation.